SMART-1 Impact Observation at the Canada-France-Hawaii Telescope
Notice bibliographique
Résumé
Introduction: Thanks to a well-planed ending of its mission, the SMART-1 spacecraft crashed on the near side of the Moon on the 3 of September 2006 at a site not illuminated by the Sun and visible from many large observatories in the Americas and the Pacific region. An observing campaign coordinated by the SMART-1 team triggered many attempts by both professional and amateur astronomers to observe the impact from the Earth. Bad weather in many observing sites and the difficulty to observe the Earthshine-lit crash site so close to the Sun-illuminated lunar surface led to only one successful observation at CanadaFrance-Hawaii Telescope and a possible detection of the impact flash by an amateur in New Mexico. The image of the impact flash, made available in near real-time by CFHT, brought visual closure to a very successful mission, and the detection of the impact plume on subsequent frames opened the possibility to study for the first time the dynamics of the ejecta from an impact on the lunar soil. Observing setup: The instrument available on the CFHT 3.6-m telescope at the time of impact was a brand new wide-field infrared camera, WIRCam. Each WIRCam image covers a 20’x20’ field, thanks to a mosaic of four very sensitive Hawaii-2 RG detectors. The 16 MPixels images are read in a few seconds. Image scale is 0.3”/pixel. With a 5-second gap between images and not knowing the exact time of impact, it was decided to set the exposure time at 10 seconds, giving a 2/3 probability of actually observing the impact. With the sunshine lit lunar surface close to the impact site and the relatively bright (for WIRCam) Earthshine lit impact area, the narrowest filter available in the camera was used: a molecular hydrogen emission filter H2 v=1-0 S(1) at 2130nm. Test images were made of the crash site the day preceding the impact, allowing a reconnaissance of the impact area and the landscape features to be used as reference for the impact observation. The impact flash: The impact did not happen between two images and was, luckily, recorded. The telescope was pointed so that the smallest portion of the mosaic would see the Sunshine lit area. The impact was therefore located very close to a corner of the mosaic. he corresponding image showing the whole detector on that corner is seen on Fig 1. Scripts processing the images in real time allowed a release of the flash image a short time after it was observed. The data actually consist in a long sequence of 10s images covering nearly an hour (20mn before the impact and 40mn after). As the Earthshine lit Moon has a very low contrast, features are not easily seen. For this work, the Virtual Moon Atlas [1] was very useful. The impact was localized on the slopes of a mountain seen on the SMART-1 image of the impact zone (Fig 3). Fig 1 The 2Kx2K detector used for the impact observation. The sunshine lit Moon is at the extreme upper right of the detector (saturated – hence black). The Earthshine lit Moon is seen with the starry sky in the background. Various ugly reflexions from the bright Moon are seen in many places... The impact flash is the bright spot at the top of the image, close to the terminator.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,007 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».